How many ways can an IRS auditor select 5 of 10 tax returns for an audit?

The number of ways an IRS auditor can select 5 tax returns from a total of 10 can be calculated using the combination formula ( C(n, k) = \frac{n!}{k!(n-k)!} ), where ( n ) is the total number of items, and ( k ) is the number of items to choose. In this case, it would be ( C(10, 5) = \frac{10!}{5!5!} = 252 ). Thus, there are 252 different ways for the auditor to select 5 tax returns for an audit.